Need to Update Lost SSH Key - Root Volume on Stopped Instance will not Force Detach

Question

I have an EC2 instance with a Root volume that has an SSH key that I do not have.  It was created by a previous administrator.  I have researched updating the key and the best approach is to unmount the volume and remount it to an instance that I do have access.  My Linux knowledge is fairly good, so if I can get the volume mounted on another server, I should be in good shape.  I have stopped (but not terminated) the affected instance.  I have tried a regular and forced volume detachment and they are failing.

Accepted Answer

**SOLVED**
I worked with AWS Support and there is a new option available for force changing the key by simply shutting down the instance, adding a script, and restarting the instance.  Details can be found here:

https://repost.aws/knowledge-center/user-data-replace-key-pair-ec2

In Step #6, replace the name "username" with the name of the user that needs to be updated (I was working with ec2-user) and replace the name "PublicKeypair" with the public key that you want that user to have on the instance.  In my case, I had a known key pair that I could use.

Brillant solution with no unmount/remount of a volume.

Need to Update Lost SSH Key - Root Volume on Stopped Instance will not Force Detach

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